Circuit breaker



Feb. 28, 1933. W. w. DASHNER 1,899,675

C IRGUIT BREAKER Filed July 8, 1929 .William lalDashneP BY www" 72W HWY-5 Patented Feb. 28, 1933 UNITED STATES PATENT OFFHCE WILLIAM W. DASHNER, F LOGANSPORT, INDIANA, ASSIGNOR TO R-B-M MANUFAC- TUBING C0., OF LOGANSPORT, INDIANA, A CORPORATION OF INDIANA CIRCUIT BREAKER Application filed July s,

This invention relates to circuit breakers, more particularly to circuit breakers for use with electrical toys.

Electrical toys, such as electric trains, toy

motors, and the like, are usually driven by current derived from a transformer connected to the house lighting circuit. These toys opera-te on a relatively low voltage supplied by the transformer, and, in case of a short circuit, such as would be caused by a part of the train jumping the track, the transformer supplies a high current to the short circuit. If allowed to continue for any length of time, this current will overheat and damage the transformer and also is liable to damage the toy itself, or to starta fire.

In my co-pending application, Serial No. 367,262, filed May 31, 1928, now Patent 1,824,125, issued September 22, 1931, I disclose a circuit breaker constructed as a self contained unit to be added to an existing electrical toy installation and arranged to be inserted in the secondary circuit of the transformer therefor and to open that circuit when the current in it becomes excessively high, as

in the case of a short circuit or the like.

The present invention relates to a new and improved circuitl breaker of the class described in the above mentioned co-pending application, the improvements tending to make the circuit breaker more reliable in its operation and, at the same time, cheaper to manufacture.

The present circuit breaker comprises a pivoted armature having a pole piece disosed at one of its ends and a contact mem- Eer at the opposite end. An electromagnet is disposed in juxtaposition to the pole piece of the armature, and a contact spring in "0 juxtaposition to the contact member on the armature. The circuit breaker is set manually by a lever attached to the armature and projecting through the cover of the circuit j breaker so that the circuit through the breakcircuit becomes excessive, the electromagnet attracts the pole piece and thereby operates the armature to open the circuit by moving m the contact on the armature away from the spring with which it is associated.

er may be closed. When the current in thisy 1929. Serial No. 376,557.

The armature is a dead armature, that is, no spring or other tension devices are employed to govern its movement, so that when the electromagnet operates it to open the circuit, the arma-ture remains in position with the circuit open after the electromagnet has become deenergized.

The armature is pivoted to move about a horizontal axis, and the armature and brackets associated with it are all formed of simple parts, thereby reducing the cost 0f manufacture of the breaker.

To acquaint those skilled in the art with the teachings of my invention, reference is made to the accompanying drawing in Which:-

Fig. 1 is a plan view of a completely assembled circuit breaker;

Fig. 2 is a plan view of the circuit breaker with the cover removed;

Fig. 3 is a side elevational view of the breaker Fig. 4; is an end view of the breaker; and

Fig. 5 is a cross sectional view taken along the line 5-5 of F ig. 2.

The completely assembled circuit breaker, shown in Fig. 1, is encased in a boxlike cover 1, that cover being attached to the base plate 7 of the breaker by suitable fastenings 5 and 6. These fastenings may be screws, rivets, or eyelets, depending upon conditions under which the breaker is to be used, the eyelets being the preferable form of fastener, since their use permits the insertion of a mounting screw through the eyelet to mount the circuit breaker upon a suitable base or support.

The upperI surface of the cover 1, is provided with a slot 2 through which the operating lever 3 of the circuit breaker is projected. A nameplate 4 is attached to the cover adjacent this slot 2. This naineplate carries, in addition tothe customary nameplate data, the notations Off and On, these notations being placed adjacent the slot as a guide indicating the `position of the breaker rela.- tive to the open or closed condition of the circuit through it.

The baseplate '7 and the cover 1 are preferably sheet metal punchings formed to the 100 Vce required shapes, the metal preferably being iron.

rThe operating parts of the circuit breakerV are mounted upon a sub-base 21, which is preferably made of an insulating material and isv attached to the base 7 by suitable eyelets or rivets.

The circuit breaker comprises the electromagnet 24, the pivoted armature 10 having the pole piece 17 disposed adjacent to the electromagnet 24, and having the insulating block 11 attached to the opposite end of itk by the rivets 12 and 18. fr spring 18 is supported on a bracket 19 in juxtaposition to the insulator 11 and the riif'et 1 2 Which attaches it to the armature 10. The bracket 19 is attached to the sub-base. 21 by suitable rivets or eyelets 20. f

'l1 he armature 10 is also provided With the foot-like project-ion 14 which extends dovvn- Wardfrom the insulator 11` adjacent to the sub-base 21. j'

The lever 14 strikes against the sub-base 1 to limit the rotation of theV Contact carrying end of the armaturelO downward toward the sub-base. The Varm 14 is designed so that Whenrit strikes the sub-base 21 the contact spring 18 is then in engagement With the rivet 12, to thereby close an electrical circuit from the Contact spring to the armature 10. T he armature 10 is pivoted by the pivot 15 to the' bracket 16,.Which bracket is attached to the sub-base 21 by suitable means, such as eyelets or rivets. rlhe pivot 15 may be a rivet, or a bolt, and, in either case, it tightly holds the armature 10 against the bracket 16 with considerable pressure, so that there is an appreciable friction in the, pivoted joint, and the armature is thereby restrained from free movement. Y

l e free movement of the armature is further limited by the arrangement of the contact spring and the rivet 12 which it en gages when the armature has been rotated to the position injvhich the arm 14 engages the sub-base 21. As will best be seen in Fig. 5, the end of the spring 18 is form-ed in a cuplike'section 18', Which engages the eyelet 12 and lits and projects into its open end. The spring 18 is tensioned so that it exerts a pressure on the eyelet longitudinally of the axis ofthe eyelet, and by this the engagement is around the rim of the Veyelet and the cup-l Ylike portion 18 of the spring, and movement of the armature 10 is resisted thereby.

As Will be seen in F ig. 5, when the armature 10 is moved upivard, spring 18 must beV moved to the left against its tension, the surface of the cup-like portion 18 riding over the open end of the eyelet 12 meanwhile.

The combined resisting action of the friction of the armature 10 With the plate 16 andY of the tension of spring 18 are relied upon to holdthe armature in the position in which it closes the Contact through the spring 18 during the flow of the normal operating current of the toy through the electromagnet 24. That is, this tension must be sutlicient so that the armature will not operate to open the circuit of the toy when the normal operating current of the toy is owing through it. Furthermore, the resistance to movement of the armature 10 must not be so great that the electromagnet 24 will be unable to operate it when an abnormally large current ows through the toy, Vfor such condition would dcfeat the purpose of the circuit breaker.

rl"he electromagnet 24 is mounted upon a foot-like bracket 22 which, in turn7 is attached to the sub-base21 by suitable rivets 23. The electromagnet comprises the usual cbre with a copper Wire Wound thereon in the formof a helix. Preferably, this Wire is of relatively large cross section so that the resistance of the magnet is lout, and its inclusion in the circuit in series with the toy will not materially reduce the voltage delivered to the toy.

The magnetic circuit of the circuit breaker is very loosely connected, there being an appreciable air gap between the end of the core of the electromagnet 24 and the pole piece 17 of the armature 10. rlhe mounting bracket 22 upon which the core of the electromagnet 24 is attached, does not come in engagement with the bracket 16 upon which the armature is attached, the space between the tivo interposing an additional air gap in the magnetic circuit of the armature. Flux generated in the electromagnet 24 spans the airgap into the pole piece 17, flows through that pole piece and the armature 10 into the bracket 16, lion/s across the auxiliary air gap from the bracket 16 into the bracket 22 andfrom there into the core of the electromagnet. rl`he looseness of this magnetic vcircuit insures that a very strong energization of the electromagnet 24 must be realized before that electromagnetcan attract the armature to open-the electrical circuit through it. y

.The electrical circuit of the circuit breaker is conducted into the breaker through the Wire 30, Which is attached to the bracket 22 by soldering or clamping at the rivet 23. The circuit is conducted from the circuit breaker by the Wire 81 similarly attached to the bracket 19 by soldering or riveting to the rivet 20. c.

The circuit in the breaker itself comprises a connection from the one end 82 of the electromagnet 24 to the bracket 22, and a confrom the contact spring 18 and the bracket 19 to the wire 31 leading from the breaker.

Preferably, the circuit breaker is included in series with the toy, that is in series with the secondary winding of the transformer that supplies current to the electrical toy. In the normal operation of the toy, the current flowing through the circuit breaker is not suiiicient to build upa suiiicient flux in the electromagnet 24 to cause it to attract the pole piece 17 of the armature. However, if the toy, such as an electrical train, for example, draws an excessively large current, as would be the case when the train jumps the track .and short circuits the rails, the electromagnet becomes sufficiently strong to attract the pole piece 17 and to rotate the armature about its pivot 15.

This rotation of the armature moves the contact spring 18 out of engagement with the eyelet 12 and into engagement with the insulator 11 which is riveted to the armature.

The electrical circuit through the breaker is thereby opened and the toy protected from injury.

The armature 10 is provided with a reset lever 3 which is preferably made of an insulating material and attached to the armature by rivets or other suitable means. This lever projects through the slot in the cover as hereinbefore pointed out, and, since it is disposed adjacent to the Off and On markings on the nameplate, it serves as a visual indicator for indicating the open or closed condition of the circuit through the breaker.

After this circuit has been opened by an overenergization of the electromagnet 24, it is necessary to manually operate the arma- .ture through the reset lever 3 to again close the circuit. This manual operation of the. lever rotates the armature about its pivot in the opposite direction, and recloses the circuit.

Inasmuch as the brackets 22, 16 and 19 are included in the electrical circuit, it is necessary that the rivets which attach these brackets to the insulating sub-base 21 be protected so that they do not come in contact with the metallic base plate 7 on which the sub-base is attached. If the rivets or other attaching means employed to attach these brackets to the sub-base were permitted to come in contact with the metallic base 7, the circuit breaker would obviously be short circuited and, therefore, inoperative. p To guard against such short circuiting of the breaker, I have provided a thin insulating strip 26 disposed between the insulator 21 and the metallic plate 7, that insulator 26 preventing the heads of the rivets disposed on `the plate side of the sub-base 21 from com-l ing in contact with the plate 7.

From the foregoing, it will be apparent that I have provided a new and improved circuit breaker Ao f simple yet rugged design,

Patent-is pointed out in the appended claims. i

What is claimed is 1. In a. circuit breaker'of the class described, a base, a bracket mounted thereon, an armature pivoted at its midpoint to said bracket, an electromagnet disposed on said base and adjacent one end of said armature and operable to move the armature in one direction about its pivot, a second bracket on said base, a spring mounted thereon and engaging said armature to close an electrical circuit through said armature and the bracket upon which the same is mounted, an insulator on said armature engaged by said spring after the armature has been moved by said electromagnet, a lever attached to said l armature for manually moving it about its pivot in the opposite direction to reestablish said circuit through it, means cooperating with said lever to indicate the position of said armature, and a projection on said armature arranged to strike said base to limit the movement of said armature by said lever.

2. In a circuit breaker of the class described, a metallic base plate, an insulating sub-base attached thereto, a plurality of brackets mounted on said sub-base, an armature pivoted to one of said brackets, said armature having a pole piece and a stop lever disposed on opposite sides of said pivot, an electromagnet attached to a second of said sub-base brackets and disposed in juxtaposition Ato said pole piece, said magnet acting on the pole piece responsive to a certain degree of energization to move the armature in one direction about its pivot, an insulator riveted to said armature adjacent said stop lever, a spring mounted on another of said brackets and engaging said vinsulator after said armature has been rotated by said magnet, a cover for said breaker mounted on said base and having a slot in one of its faces, and a lever on said armature and projecting through said slot, said lever indicating the position of the armature and being operable to rotate the armature in the opposite direction to move one of the rivets which hold the insulator to said armature into engagement with said spring to close a circuit through the armature and the bracket upon which the same is mounted,

,said stop lever then stopping the movement of Y',

said armature. v

. 3. An overload circuit breaker for electrical toys comprising, a base, an electromagnet mounted upon said base, a bracket mounted on the base adjacent said magnet, an armature pivotally mounted on said bracket, an insulator, rivet means attaching said insulator to the free end ofsaid armature, a second bracket mounted on said base adjacentthe free end of said armature, a spring attached to said second bracket and engaged with said insulator when said armature is engaged with said electromagnet, a lever attached .to said armature for moving it about its pivot away from said magnet to thereby bring said spring into engagement with said rivet means to establish an electrical connection between the spring and armature, said circuit breaker including means for estab'- lishing an electrical connection between said armature bracket and one end of said electromagnet, and conductors connected to the Aother end of said electromagnet and to said second bracket to permit connecting the breaker in circuit with the toy, said electromagnet operating the armature responsive to an overload condition to open the electrical connection between said spring and arma.- ture, a cover for said breaker having a slot through which said lever projects and means on the cover cooperating with the lever to indicate theopenfor closed condition of said circuit.

In witness whereof, I hereunto subscribe my name this 27 th day of June, 1929.

WILLIAMW. DASHNER. 

